Pressure relief valve and alarm



Sept 22, 1970 -i y A. FERRARI 3,529,625

PRESSURE RELIEF VALVE AND ALARM Filed Oct. 25, 1967 INVENTOR, ANDRES FERRARI United States Patent O 3,529,625 PRESSURE RELIEF VALVE AND ALARM Andres Ferrari, Scarsdale, N.Y., assignor to Technicon Corporation, Ardsley, N.Y., a corporation of New York Filed Oct. 25, 1967, Ser. No. 678,105 Int. Cl. F16k 15/04, 37/00 U.S. Cl. 137--554 4 Claims ABSTRACT OF THE DISCLOSURE A conduit, which is part of an analytic system, carrying a liquid, has an open topped vertical tube coupled thereto by a bottom inlet. A valve seat is formed on the inlet, and receives a check ball, which may be loaded by weights, all slidable in the tube. A U-shaped tube has one leg thereof coupled to said vertical tube below the top thereof and the other leg thereof coupled to an inverted U-shaped tube. An electrode is disposed in the bottom of the U-shaped tube, and another electrode is adjustably disposed in said other leg of said U-shaped tube.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to pressure relief valve and alarm devices and especially to such devices for continuous automatic analysis apparatus.

Prior art Apparatuses for the automatic, continuous analysis of liquids are well known. Such an apparatus s shown in U.S. Pat. No. 2,797,149 issued June 25, 1957 to L. T. Skeggs. The analysis apparatus is fed sequential samples as a continuous stream by means of an off-take device which aspirates liquid from each of a plurality of sample containers, which are sequentially presented thereto by a sampler assembly, as shown in U.S. Pat. No.' 2,879,141 issued March 24, 1959 to L. T. Skeggs. Alternatively, the analysis system may be monitoring a production system and be supplied with a continuous sample. More recently, apparatus has become known wherein the initial continuous stream of samples is divided into a plurality of quotient streams, each containing a fractional portion of each sample from the initial stream. Each quotient stream is then analyzed, and the results are recorded in correlation automatically. Such an apparatus is shown in U.S. Pat. No. 3,241,432 issued Mar. 22, 1966` to L. T. Skeggs et al.

These apparatuses include manifolds of relatively small internal diameter and relatively long length, wherein it is possible, especially in monitoring systems, for internal pressures to build up and to cause tubes or connections to rupture. This situation becomes less unlikely to occur the longer the apparatus is to operate unattended, as in the case of atmosphere pollution monitors, which may be left unattended in a remote area from day to day.

SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide a means to relieve the pressure in a manifold should it build up above a threshold level, and to set off an alarm should the over-pressure situation continue for a predetermined interval of time. Liquid which is lost from the manifold in relieving the pressure should be safely conveyed away from the apparatus.

The principles of this invention are comprised in an upwardly directed tube coupled to the manifold at such place as pressure is most likely to build up. The tube is normally closed by a pressure sensitive valve, such as a check ball. When the valve opens under an increase in pressure, liquid from the manifold passes into a reservoir.

3,529,625 Patented Sept. 22, 1970 ICC When the over-pressure is relieved, the valve closes. When the reservoir is filled to a predetermined level, it closes an alarm circuit. When the reservoir is overlilled, the surplusage is conveyed to waste.

BRIEF DESCRIPTION OF THE DRAWING FIG. l is a view in elevation, in cross-section, of an apparatus embodying this invention; and

FIG. 2 is a view n elevation, in cross-section, of a modification of the apparatus of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a conduit 10 forms part of a manifold, such as is shown in U.S. Pats. Nos. 2,797,149 and 3,241,432, supra. An upwardly directed tube 12, which forms a first chamber or reservoir, is coupled to the conduit 10, as by an integrally formed junction. The lower portion 14 of the column 12 is reduced in internal diameter to form a valve seat 16 for a check ball 18. The ball 18 is loaded by one or more weights 20, 22 and 24, and all are slidable, with clearance, within the tube 12. The ball normally rests on the valve seat, and closes the aperture 26 therebelow to the conduit 10. The total weight of the weights and the ball over the cross-sectional area of the aperture 26 is arranged to be greater than the pressure normally developed in the conduit, and less than any over-pressure which it is desired to relieve. Should an over-pressure be developed in the conduit 10, it will be communicated through the aperture 26 to raise the ball 18 and to pass liquid from the conduit 10 around the ball and the weights into the tube 12.

The upper end of the tube 12 is open to the atmosphere, to preclude a back-pressure against the check ball. A bridge tube or liquid outlet 30 connects the upper portion of the tube 12, below its upper end, to a second chamber or tube 31, whose upper end is also open to permit an equilibrium of pressure through the bridge. The lower portion of the tube 31 may be reduced in diameter and is bent into a main U-shape 32, which terminates in a reversed or inverted U-shape 34 or syphon, whose uppermost part is lower than the bridge 30'.

The electrode 36 is fixed within the bottom of the lmain U-shape 32, and a movable electrode 38 is slidably mounted within the downstream 40 arm of the main U- shape, as shown by the arrows 44. The two electrodes are series-coupled to a suitable relay and battery circuit 41, which controls a battery circuit 42 for operating a suitable alarm A and a system shutdown device S, if desired. The opening of the electrode 38 from the electrode 36 is adjustable to predetermine the volume of liquid disposed in the main U-shape which will be adequate to set off the alarm. As more and more liquid passes through the aperture 26, it will rise to the tube 12, pass through the bridge 30, into the tube 31, and fall into the main U-shape 32. If the over-pressure condition is a transient, a volume of liquid may be passed through the aperture 26 which is adequate to relieve the over-pressure condition, but inadequate to shunt the electrodes. In this event, the system will continue operating. If the over-pressure condition repeats itself, eventually enough liquid will be passed through the aperture to shunt the electrodes. Similarly, if the over-pressure condition is a steady-state condition, enough liquid will be passed through the aperature to shunt the electrodes and operate the relay 43. Extra liquid will pass out through the syphon 34 to waste; however, in such an event, enough liquid will always remain in the main U-shape to shunt the electrodes.

'Ihe threshold pressure necessary to displace the check ball 18 may be adjusted by varying the weights 20, 22 and 24 used to load the ball. Alternatively, for very tine 3 adjustments, as shown in FIG. 2, a tube 100, which is closed at its lower end, and which may be filled with any desired quantity of divisible material 102, such as metal powder, may be substituted for the weights.

What is claimed is:

1. A pressure-relief valve and delayed alarm device comprising: means defining a conduit, for a substantially horizontal flow of liquid through a portion thereof subject to pressure increases, and also defining thereabove a substantially vertical first chamber in communication with said portion, said means further defining an orice intermediate said portion and said chamber, a pressureresponsive valve normally closing said orice against the flow of liquid into said chamber from the conduit, the upper end of the chamber being in communication with the atmosphere, said chamber being normally free of liquid and forming a reservoir for liquid from the conduit when a predetermined liquid pressure on the valve causes the latter to open, means defining an outlet for excess liquid from the reservoir adjacent the upper end of the latter, means in communication with said liquid outlet deiining a second vertical chamber normally free of liquid, extending below the level of said outlet for receiving excess liquid from the reservoir, and switch means, coupled to said second chamber, normally in a first state and shiftable to a second state in response to the liquid in the second chamber reaching a predetermined level therein.

2. A device as defined in claim 1, wherein said second chamber is of U-shape, having the distal end portion of one leg thereof connected to said means defining a liquid outlet, and having the other leg thereof connected to means defining a reversely curved syphon conduit below said outlet for discharging excess liquid in said second chamber.

3. A device as defined in claim 2, wherein said switch means comprises a first electrode disposed within the lower portion of said U-shaped chamber and a second electrode disposed within said other leg of the U-shaped chamber.

4. A device as defined in claim 3, wherein said second electrode is adjustable in its spacing fro-m said first electrode to vary the liquid level required to shift said switch means to said second state.

References Cited UNITED STATES PATENTS HENRY T. KLINKSIEK, Primary Examiner U.S. Cl. X.R. 23-253; 73-40.5 

